'Einstein Was Right: You Can Turn Energy Into Matter'

Albert Einstein proposed the most famous formula in physics in a 1905 paper on Special Relativity titled Does the inertia of an object depend upon its energy content?

Essentially, the equation says that mass and energy are intimately related. Atom bombs and nuclear reactors are practical examples of the formula working in one direction, turning matter into energy.

But until now there has been no way to do the reverse, turn energy into matter. What makes it particularly hard is that c2 term, the speed of light squared. It accounts for the huge amounts of energy released in nuclear reactions, and the huge amount you’d need to inject to turn energy into matter.

Previous experiments have always required a little bit of mass, even if it was only an electron’s worth.

But scientists at Imperial College London (including a visiting physicist from Germany's Max Planck Institute for Nuclear Physics) think they’ve figured out how to turn energy directly into matter.

Oliver Pike, Felix Mackenroth, Edward Hill and Steve Rose have suggested a way to turn a pair of photons, particles of light, into an electron and its antiparticle, a positron.

They came up with the idea in less than a day, over several cups of coffee at Imperial’s Blackett Physics Laboratory.

They started off talking about fusion, but realised their work could be applied to an earlier problem, an idea proposed by two US scientists, Gregory Breit and John Wheeler, in 1934.

Breit and Wheeler, who went on to work on America’s Manhattan Project to build the first A-bomb, thought it was theoretically possible to smash two photons together to produce an electron and a positron.

“Despite all physicists accepting the theory to be true, when Breit and Wheeler first proposed the theory, they said that they never expected it be shown in the laboratory,” said Professor Rose. “Today, nearly 80 years later, we prove them wrong.”

Their article in Nature Photonics proposes that a new kind of collider be built, one that smashes photons instead of protons, as at the Large Hadron Collider at CERN where the Higgs boson was discovered last year.

Their accomplishment has huge implications, not only does it yet again prove an aspect of Einstein’s theories, it recreates a “process that was important in the first 100 seconds of the universe and that is also seen in gamma ray bursts, which are the biggest explosions in the universe,” said Imperial.

The first step would be to accelerate electrons with a high-energy laser to just below the speed of light (300,000km/s) and smash them into a slab of gold, which would create a beam of light a billion times more intense than the light from the Sun.

This would be aimed into a hollow gold shell called a hohlraum (German for empty room). The shell would be excited by another laser to create a thermal radiation field that emits light akin to starlight.

When the two sources of light cross, some will collide and create electrons and their corresponding antimatter particles, positrons, which could be detected as they left the hohlraum. They calculate that the experiment should produce 100,000 pairs of particles.

“What was so surprising to us was the discovery of how we can create matter directly from light using the technology that we have today,” said Rose. “As we are theorists we are now talking to others who can use our ideas to undertake this landmark experiment.”

Pike, the lead author on the paper, said: "Although the theory is conceptually simple, it has been very difficult to verify experimentally. We were able to develop the idea for the collider very quickly, but the experimental design we propose can be carried out with relative ease and with existing technology. Within a few hours of looking for applications of hohlraums outside their traditional role in fusion energy research, we were astonished to find they provided the perfect conditions for creating a photon collider. The race to carry out and complete the experiment is on."

Among candidate locations for the experiment are the Omega laser in Rochester, New York and the
Orion laser at Aldermaston, the UK atomic weapons facility in Berkshire.

I’ve been a working journalist for more than a quarter of a century, much of it freelance, with a particular interest in science, technology and medicine. My experience includes writing for The Economist’s science section, The Independent on Sunday, The Telegraph, New Scient...